Moore was promoted to post-captain on 2 April 1794, soon after the start of the Revolutionary War, with command of the 32-gun frigate Syren,[2] in the North Sea and the coast of France. He then commanded the 36-gun frigate Melampus from September 1795.[1] In her he took part in the Battle of Tory Island on 12 October 1798, capturing the French frigate Résolue two days later.[2] In February 1800 he went out to the West Indies, but was invalided home after eighteen months.[1]

On the renewal of the war in 1803 he was appointed to Indefatigable (44),[1] and with three other frigates — Medusa (32), Lively (38) and Amphion (32) — under his command, captured a Spanish treasure fleet of four frigates — Medea (40), Clara (34), Fama (34) and Mercedes (36) — carrying bullion from the Caribbean back to Spain off Cadiz in the Action of 5 October 1804.[1]